#include "archive.hh"
#include "builtins.hh"
#include "compression.hh"
#include "download.hh"
#include "store-api.hh"

namespace nix {

void builtinFetchurl(const BasicDerivation& drv, const std::string& netrcData) {
  /* Make the host's netrc data available. Too bad curl requires
     this to be stored in a file. It would be nice if we could just
     pass a pointer to the data. */
  if (netrcData != "") {
    settings.netrcFile = "netrc";
    writeFile(settings.netrcFile, netrcData, 0600);
  }

  auto getAttr = [&](const string& name) {
    auto i = drv.env.find(name);
    if (i == drv.env.end())
      throw Error(format("attribute '%s' missing") % name);
    return i->second;
  };

  Path storePath = getAttr("out");
  auto mainUrl = getAttr("url");
  bool unpack = get(drv.env, "unpack", "") == "1";

  /* Note: have to use a fresh downloader here because we're in
     a forked process. */
  auto downloader = makeDownloader();

  auto fetch = [&](const std::string& url) {
    auto source = sinkToSource([&](Sink& sink) {
      /* No need to do TLS verification, because we check the hash of
         the result anyway. */
      DownloadRequest request(url);
      request.verifyTLS = false;
      request.decompress = false;

      auto decompressor = makeDecompressionSink(
          unpack && hasSuffix(mainUrl, ".xz") ? "xz" : "none", sink);
      downloader->download(std::move(request), *decompressor);
      decompressor->finish();
    });

    if (unpack)
      restorePath(storePath, *source);
    else
      writeFile(storePath, *source);

    auto executable = drv.env.find("executable");
    if (executable != drv.env.end() && executable->second == "1") {
      if (chmod(storePath.c_str(), 0755) == -1)
        throw SysError(format("making '%1%' executable") % storePath);
    }
  };

  /* Try the hashed mirrors first. */
  if (getAttr("outputHashMode") == "flat")
    for (auto hashedMirror : settings.hashedMirrors.get()) try {
        if (!hasSuffix(hashedMirror, "/")) hashedMirror += '/';
        auto ht = parseHashType(getAttr("outputHashAlgo"));
        auto h = Hash(getAttr("outputHash"), ht);
        fetch(hashedMirror + printHashType(h.type) + "/" +
              h.to_string(Base16, false));
        return;
      } catch (Error& e) {
        debug(e.what());
      }

  /* Otherwise try the specified URL. */
  fetch(mainUrl);
}

}  // namespace nix